Reducing Defects in Garage Door Panels Through PDCA-Based Process Improvement

Abstract

This design project applies the Plan–Do–Check–Act (PDCA) methodology to analyze and reduce defects in garage door panel manufacturing. A dataset of 30 nonconforming panels was examined to identify defect types, severity levels, locations, and dispositions. Pareto analysis, defect severity evaluation, heat mapping, and a cause-and-effect diagram were used to identify dominant defect patterns and likely root causes. Based on the findings, corrective and preventive improvement actions were developed targeting handling practices, equipment contact, material protection, inspection standardization, and workplace layout. The effectiveness of these actions was evaluated using a simulated post-improvement dataset reflecting realistic first-cycle PDCA results. The simulation showed a reduction in total defects from 30 to 17, representing a 43% improvement. Both customer-perceived quality (fraction defective) and internal process performance (defects per unit) showed measurable improvement. The results demonstrate that PDCA provides a structured, data-driven approach for diagnosing quality problems and guiding sustainable defect reduction in manufacturing environments. Keywords ⎯ Continuous Improvement, Defect Reduction, Manufacturing Quality, PDCA.